Laminitis—the inflammation of the soft tissue (sensitive laminae) within the hoof—can cause a horse excruciating pain. In severe cases, the sensitive laminae weaken to the point where they can’t support the coffin bone, which then sinks or rotates, pulling away from the interior of the hoof wall—a condition called “founder.” In these severe cases, this damage cannot be undone, and the horse may be left permanently unsound. In the worst cases, euthanasia may be the only humane option.
There are two forms of laminitis: An acute episode occurs rapidly and may respond to appropriate, intensive treatment; the chronic form is a persistent, long-term condition that can be difficult to treat. To protect your horse from either type of this devastating disease, identify the factors that might put him at risk, take the appropriate preventive measures and be ready to respond should you notice early signs of the disease.
Common risk factors for laminitis
Any horse can develop laminitis if he binges on grain, but even small or “normal” portions of starches and sugars can trigger the disease in horses whose health status and/or history make them susceptible to the disorder. Several factors put horses at greater risk for laminitis:
• Equine metabolic syndrome (EMS) is the term used for a collection of signs that usually includes obesity, insulin resistance and infertility. Horses with EMS tend to gain weight easily, and they are likely to have noticeable fat deposits on the crest of the neck, over the tailhead and behind the shoulder. EMS is managed primarily through diet and exercise.
• Pituitary pars intermedia dysfunction (PPID, also called Cushing’s disease) is most commonly characterized by a long hair coat that is slow to shed out in spring, but other signs include excessive sweating, lethargy, increased thirst and urination, and an increased susceptibility to infections. PPID can be controlled with the drug pergolide (brand name Prascend), along with management of diet and exercise.
• Severe injury or systemic illness, such as pleuropneumonia or Potomac horse fever, puts horses at risk of laminitis as a complication.
• Stresses on the hooves or a single limb can damage the sensitive laminae leading to mechanical laminitis, even if a horse is not otherwise at risk for the condition. For example, the concussion produced by fast work over extremely hard ground can cause laminitis, as can the stresses placed on the hoof by persistent imbalances. Likewise, a serious ortho- pedic injury that forces a horse to bear more weight than usual on a particular limb increases the risk of laminitis—this is known as opposite-limb laminitis.
• Ponies, certain breeds and certain bloodlines are more likely to develop conditions such as PPID and EMS that make them more sus-ceptible to laminitis.
A general management strategy for reducing laminitis risk
1. Grazing. Some horses can eat large quantities of new grass without any trouble, but others may develop laminitis after eating just small amounts of lush grass. In fact, most laminitis cases are caused when horses graze too much on rich pasture, particularly in the spring and fall when grass can be high in sugars. Talk to your veterinarian about your horse’s risk; you may need to limit his access to lush pasture, fit him with a grazing muzzle or temporarily move him to a dry lot.
2. Diet. Reduce the sugars and starches in the diet of horses who have had laminitis, are insulin resistant or are otherwise at risk. Many low-sugar feeds are now available as substitutes for sweet feeds that contain molasses or other sugars. In fact, many feed companies offer products specifically formulated for laminitis prevention. And don’t forget that some treats can be high in sugars: For at-risk horses, stick to small amounts of carrot slices or peanuts in the shell.
3. Hoof care. Overgrown and unbalanced hooves can develop mechanical laminitis. And should laminitis occur, neglected hooves are more likely to founder than are healthy, balanced hooves. Keep your horse on a regular (every six to eight weeks) farriery schedule.
4. Weight maintenance. The relationship between obesity, metabolic dysfunction and laminitis is not entirely understood, but one thing is clear: Obese horses are far more likely to develop laminitis than are those at optimal weight. Periodically assess your horse’s body condition—and, if he’s starting to put on excess pounds, devise a diet and exercise plan to address the issue.
Signs of laminitis
Call your veterinarian right away when you notice any of these signs; tell her what you’ve observed and explain that it’s an emergency:
• Your horse is “ouchy” and reluctant to move. He may shift his weight back and forth between his front feet, or he may lean back on his haunches with his forefeet splayed in front of him. In some cases, he may stand with all four feet pulled in under his barrel.
• He lies down and is reluctant to rise.
• He shows evidence of pain, which may include sweating, shallow breathing and a rapid heart rate.
• The affected hoof or hooves feel warm to the touch.
• You feel a “bounding” pulse on the back of the pastern on the affected legs. This pulse can be difficult to locate on a healthy horse, but it becomes more prominent either just above or just below the joint when a horse has laminitis.
What to do if you suspect laminitis
Even as you wait for your veterinarian, take steps to stop the progress of the laminitis and set the stage for your horse’s treatment and recovery:
• Ice the affected feet. Researchers have found that placing the horse’s feet in ice at the earliest sign of trouble reduces the severity of laminitis. This treatment can even prevent the disease entirely if, for example, your horse has broken into the grain bin and you suspect laminitis may develop. You’ll want to stand the horse in a tub filled with ice and cold water deep enough to reach the middle of the cannon bone.
• Keep the horse still. You don’t want to walk a horse with laminitis because the stresses on his feet may damage the weakened laminae. If he really can’t be left where you found him until the veterinarian arrives, choose the shortest route over the softest footing that is possible. It may be worthwhile to bring a trailer to the horse and let him ride to the barn.
• Take the horse’s vital signs. A fever might indicate that your horse has an underlying illness you hadn’t noticed, and data such as his pulse and rate of breathing offer insights into the severity of his pain. Make notes of your findings, and the time you recorded them, to share with your veterinarian.
This article was originally published the EQUUS #475
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